The present invention relates to a color filter which is obtained by coloring a picture element part with an ink jet system and which is suitable for a color liquid crystal display and a process for producing the same.
Recently, there has been a tendency that a demand for a liquid crystal display, particularly a color liquid crystal display is increasing with the development of a personal computer, particularly a portable personal computer. However, since this color liquid crystal display is expensive, a demand for the cost-cut is getting higher and, in particular, a demand for the cost-cut of a color filter weighing in a respect of cost is high.
In such a color filter, a liquid crystal usually operates as a shutter by equipping with three primary colors of red (R), green (G) and blue (B) and switching ON and OFF of an electrode corresponding to each picture element part of R, G and B and the color display is performed by transmission of the light through each picture element part of R, G and B.
As a process for producing a color filter which has hitherto been carried out, there is, for example, a dyeing process. In this dyeing process, a water-soluble polymer material which is a material for dyeing is first formed on a glass substrate, which is patterned into the desired shape by a photolithography step and the resulting pattern is dipped into a dyeing bath to obtain a colored pattern. This is repeated three times to form a color filter layer consisting of picture element parts of R, G and B.
Alternatively, as an another method, there is a pigment dispersing method (color resist method). In this method, a photosensitive resin layer in which a pigment is dispersed is first formed on a substrate and this is subjected to patterning to obtain a monocolor pattern. Further, this step is repeated three times to form a color filter layer consist of picture element parts of R, G and B.
As a still another method, there are an electrode position method and a method of dispersing a pigment in a thermosetting resin and performing three times printing of R, G and B and, thereafter, thermally curing the resin. However, in any method, the same step needs to be repeated three times for coloring three colors of R, G and B, and there is a problem that the cost is high and a yield is decreased because of repetition of a step.
As a process for producing a color filter which has solved these problems, there is proposed a method of blowing a coloring ink with an ink jet system to form a colored layer (picture element part) (JP-A-59-75205). In the publication, there are disclosed a method in which a convex part which is a border is printed in advance with a material having the worse wettability on an ink when an ink having the better wettability on a glass substrate is used, and a method in which a pattern is formed in advance with a material having the better wettability on an ink to help the ink fixation when an ink having the worse wettability on a glass is used. However, there is no description regarding how to specifically coat a material having the better wettability and a material having the worse wettability.
On the other hand, as another process for producing a color filter by blowing a coloring ink by an ink jet system to form a colored layer (picture element part), there is disclosed a method of treating a concave part with an inkphilic treating agent in JP-A-9-203803. In this method, a convex part is formed in advance on a substrate and this convex part is made to be ink-repellent and, thereafter, the whole substrate is surface-treated with the inkphilic treating agent. However, in this method, since a convex part needs to be ink-repellent in advance upon the inkphilic treatment, there is a problem that two times treatments of the ink-repulsion treatment and the inkphilic treatment need to be performed.
In addition, as a method for producing a color filter by forming a colored layer with an ink jet system, there is described a method of forming a colored layer (picture element part) by providing an ink absorbing layer on a substrate and making a difference in the ink absorbability of this absorbing layer between an exposed part and an unexposed part in JP-A-8-230314 and JP-A-8-227012. However, in this method, since a colored layer is formed by forming an absorbing layer and absorbing an ink in this absorbing layer, there is a problem that a difference in the coloration between a central part of an ink dot and a surrounding part of that is present which results in the color nonuniformity. In addition, there is also a problem that this absorbing layer needs the predetermined thickness resulted from its function of absorbing an ink.
The present invention was done in view of the above problems and a main object thereof is to provide a color filter in which a part having the better wettability and a part having the worse wettability can be formed on a single layer regarding the wettability of a substrate which becomes problematic upon formation of a picture element part with an ink jet system, and a pattern formed of the part having the better wettability and the part having the worse wettability can be formed in a few steps and, further, an ink absorbing layer is not necessary, and which has the better quality and which can be produced with the low cost, and a process for producing the same.
In order to attain the aforementioned object, the present invention provides a color filter which comprises a transparent substrate, a picture element part in which a plurality of colors are provided in the predetermined pattern with an ink jet system on the transparent substrate, a shading part provided on a border part of the picture element part, and a wettability-variable layer being capable of varying the wettability which is provided for forming the picture element part, or the picture element part and the shading part.
As described above, the present invention is characterized in that it has a wettability-variable layer in order to form a picture element part, or a picture element part and a shading part. Therefore, by utilizing the change in the wettability of a wettability-variable layer, a picture element part, or a picture element part and a shading part can be formed with the better precision, and a high quality color filter having no problem such as color missing and color nonuniformity can be provided.
In this case, the construction may be such that at least the picture element part is provided on the wettability-variable layer. By forming a picture element part on the wettability-variable layer like this, a wettability-variable layer of a part on which a picture element part is formed can be made to be an inkphilic region having a small contact angle with a liquid. By coloring a picture element part forming portion which is an inkphilic region with an ink jet system, an ink is adhered to only the picture element part forming portion which is an inkphilic region having a small contact angle with a liquid, and further an ink is applied uniformly within the picture element part forming portion which is an inkphilic region. Therefore, a color having no disadvantage such as color nonuniformity and color missing can be provided.
In the present invention, when at least the picture element part is provided on a wettability-variable layer, the following three kinds of constructions can be adopted. First is the construction in which the shading part is provided on the transparent substrate, the wettability-variable layer is provided on this shading part and a picture element part forming portion on which the picture element part on the transparent substrate is provided, and further, the picture element part is formed on this wettability-variable layer (a color filter, in which a picture element part is formed on a wettability-variable layer and a wettability-variable layer is provided on a shading part, is referred to as the first embodiment hereinafter). Second is the construction in which a wettability-variable layer is formed on the transparent substrate and a picture element part and a shading part are provided on the predetermined position of this wettability-variable layer (a color filter, in which a picture element part and a shading part are provided on a wettability-variable layer, is referred to as the second embodiment hereinafter). Third is the construction in which the shading part is provided on the transparent substrate, a wettability-variable layer is provided on a picture element part forming portion on which a picture element part on the transparent substrate is formed, and a picture element part is formed on this wettability-variable layer (a color filter, in which a picture element part is formed on a wettability-variable layer and a wettability-variable layer is not formed on a shading part, is referred to as the third embodiment hereinafter).
In the aforementioned first embodiment, it is preferable that the width of the picture element part provided on the wettability-variable layer is wider than the width of an opening formed by the shading part. This is because, by forming the width of the picture element part so as to be wider than the width of an opening of a shading part like this, the disadvantages such as color missing that a backlight passes through a part on which a picture element part is not formed, can be prevented.
In the present invention, it is preferable that an ink-repellent convex part is formed on a surface of a wettability-variable layer provided on the shading part. Since by forming an ink-repellent convex part on the surface of a wettability-variable layer provided on a shading part like this, an ink-repellent convex part is formed between the picture element part forming portions upon forming the picture element part by making a wettability-variable layer of a picture element part forming portion into an inkphilic region, the disadvantages such as mixing of inks do not occur, being preferable.
In this case, it is preferable that the width of the ink-repellent convex part is narrower than that of the shading part. This is because by forming the width of an ink-repellent convex part narrower than that of a shading part like this, the width of a picture element part formed between the ink-repellent convex parts can be formed wider than the width of an opening formed by a shading part and, thus, the aforementioned effects can be obtained.
On the other hand, in a color filter of the present invention, the construction may be such that the wettability-variable layer is provided on a border part of the picture element part. By making the wettability of a wettability-variable layer on a border part of a picture element part, an ink-repellent region having the larger contact angle with a liquid than that of a part on a transparent substrate on which a picture element part is formed like this, since it is difficult for an ink to migrate over a border part of a picture element part having the ink-repellent properties upon coloring a part on which a picture element part is provided (picture element part forming portion) with an ink jet system, a color filter having no disadvantages such as ink mixing and the like can be provided. In addition, by making a wettability-variable layer of a border part of a picture element part an inkphilic region having the small contact angle with a liquid thereafter, providing of the shading part on the border part of the picture element part or covering the whole with a protecting layer can be easily carried out and, thus, a color filter having the high quality can be obtained.
In this case, there are two preferable constructions. One of these is the construction in which the shading part is formed on the transparent substrate, a wettability-variable layer is formed on this shading part and the picture element part is formed between the wettability-variable layers (a color filter, in which a wettability-variable layer is provided on a shading part, is referred to as the fourth embodiment hereinafter). Another one is the construction in which the wettability-variable layer is formed on a shading part forming portion which is a part on which a shading part on the transparent substrate is formed, the shading part is formed on the wettability-variable layer, and a picture element part is formed between the shading parts (a color filter, in which a shading part is formed on a wettability-variable layer, is referred to as the fifth embodiment hereinafter).
In the fourth embodiment, it is preferable that the width of the wettability-variable layer is formed narrower than that of a shading. By making the width of a wettability-variable layer narrower than that of a shading part, the width of a picture element part formed between wettability-variable layers can be formed larger than that of an opening of a shading part. This is because, thereby, the disadvantages such as color missing and the like can be prevented.
In the aforementioned third embodiment and a color filter described above, in which the wettability-variable layer is provided on a border part of the picture element part, it is preferable that the wettability on the transparent substrate is less than 10 degrees in terms of the contact angle with a liquid having the surface tension of 40 mN/m. This is because, in the aforementioned third embodiment, an ink for a shading part is spread uniformly within a shading part forming portion and it becomes possible to form a uniform shading part with the better precision and, additionally, in the case of a color filter in which a wettability-variable layer is provided on a border part of the picture element part, since an ink for the picture element part is uniformly spread with a picture element part forming portion on a transparent substrate, the better-quality color filter having no disadvantages such as color nonuniformity and the like can be provided.
In the present invention, it is preferable that the wettability-variable layer is a photocatalyst-containing layer comprising at least a photocatalyst and a binder, and having the wettability which varies so that the contact angle with a liquid is decreased by irradiation with the energy. Like this, by forming a photocatalyst-containing layer having the wettability which varies so that the contact angle with a liquid is decreased by irradiation with the energy, the wettability of this layer can be varied by performing the pattern irradiation of the energy and the like and an inkphilic region having the small contact angle with a liquid can be formed easily and, for example, it becomes possible to easily make only a part on which a picture element part is formed into an inkphilic region. This is because, therefore, a color filter can be manufactured effectively and it becomes advantageous in a respect of cost.
In a color filter described above, it is preferable that the photocatalyst-containing layer contains fluorine and the photocatalyst-containing layer is formed so that the content of fluorine on the surface of the photocatalyst-containing layer is decreased by the action of the photocatalyst as compared with before the irradiation of the energy upon irradiating the photocatalyst-containing layer with the energy.
As mentioned above, since a color filter of the present invention is constructed such that the fluorine content of the energy irradiated part on a photocatalyst-containing layer formed on a transparent substrate is decreased, a pattern comprising a part in which the fluorine content is decreased can be formed by the pattern-irradiation of the energy. Since when the fluorine content is decreased, the part becomes a region having the high inkphilicity as compared with other parts, it becomes possible to easily make only a part on which a picture element part and the like is formed an inkphilic region, and a color filter can be easily manufactured.
Further, in a color filter described above, it is preferable that the fluorine content of a part in which the fluorine content is decreased by irradiating the photocatalyst-containing layer with the energy, is 10 or less relative to 100 of the fluorine content of a part which was not irradiated with the energy.
When, like this, the fluorine content of a part having the lower fluorine content which was formed by irradiating the photocatalyst-containing layer with the energy, is 10 or less based on the weight relative to 100 of the fluorine content of a part which is not irradiated with the energy, a great difference in the inkphilicity between a part irradiated with the energy and a part not irradiated with the energy can be produced. Therefore, by forming a picture element part and the like on a photocatalyst-containing layer on which such the pattern is formed, it becomes possible to precisely form a picture element part and the like on only an inkphilic region having the reduced fluorine content and a color filter can be manufactured with the better precision.
In the case that a photocatalyst-containing layer used in the present invention comprises at least a photocatalyst and a binder as described above, it is preferable that the photocatalyst is one or more selected from the group consisting of titanium oxide (TiO2), zinc oxide (ZnO), tin oxide (SnO2), strontium titanate (SrTiO3), tungsten oxide (WO3), bismuth oxide (Bi2O3), and iron oxide (Fe2O3). Inter alia, titanium oxide (TiO2) is preferable. This is because since titanium oxide has the high band gap energy, it is effective as a photocatalyst, is chemically stable, has no toxicity and is easily available.
In the case of a color filter in which a photocatalyst is titanium oxide, it is preferable that it has a photocatalyst-containing layer in which fluorine element is contained in the surface of the photocatalyst-containing layer at an amount of 500 or more relative to 100 of titanium element as quantified by a X-ray photoelectron spectroscopic method.
This is because, when such the degree of fluorine (F) element is contained, the ink-repellent properties of a part not irradiated with the energy are sufficient and, when a pattern of a part having the reduced fluorine (F) element content by the energy irradiation is formed and a picture element part and the like are formed thereon, an ink and the like do not drop out into a part other than a part on which a picture element part is formed and a color filter can be manufactured more precisely.
On the other hand, in a color filter described above, a binder which is the other component constituting a photocatalyst-containing layer is preferably organopolysiloxane having a fluoroalkyl group.
The reasons are as follows. In a color filter of the present invention, as a method of inclusion of fluorine element in a photocatalyst-containing layer, mention may be made of various methods. However, by using organopolysiloxane having a fluoroalkyl group as a binder, fluorine element can be easily contained in a photocatalyst-containing layer and the content thereof can be easily reduced by the energy irradiation.
In addition, in a color filter described above, it is preferable that a binder which is the other component constituting a photocatalyst-containing layer, is formed of organopolysiloxane which is one or more of a hydrolyzed condensed compound or a co-hydrolyzed condensed compound of a silicon compound represented by YnSiX(4xe2x88x92n) (wherein Y represents alkyl group, fluoroalkyl group, vinyl group, amino group, phenyl group or epoxy group, X represents alkoxy group or halogen, and n is an integer of 0 to 3).
In a color filter described above, it is preferable that a silicon compound having a fluoroalkyl group among the aforementioned silicon compounds constituting the aforementioned organopolysiloxane is contained at an amount of not less than 0.01 mol %.
The reasons are as follows. When a silicon compound having a fluoroalkyl group is contained at an amount of not less than 0.01 mol %, fluorine element is sufficiently contained in the surface of a photocatalyst-containing layer and it is possible to make larger the difference in the wettability between an inkphilic region on a photocatalyst-containing layer having the reduced fluorine element content resulted from the energy irradiation and an ink-repellent region on the surface of a photocatalyst-containing layer not irradiated with the energy. Accordingly, an ink and the like can be precisely attached into an ink-repellent region without dropping out upon formation of a picture element part and the like on an inkphilic region, and a color filter having the better quality can be manufactured.
In the present invention, it is preferable that the contact angle with a liquid having the surface tension of 40 mN/m on the photocatalyst-containing layer is 10 degrees or more in a part not irradiated with the energy and the angle is less than 10 degrees in a part irradiated with the energy. Since a part not irradiated with the energy is a part requiring the ink-repellent properties, when the contact angle with a liquid having the surface tension of 40 mN/m is less than 10 degrees, the ink-repellent properties are not sufficient and there is a possibility that an ink and a coating material for a shading part and the like remain, being not preferable. On the other hand, when the contact angle of a part irradiated with the energy with a liquid having the surface tension of 40 mN/m is 10 degrees or more, there is a possibility that the spread of an ink and a coating material for a shading part is inferior, color missing and the like may occur in a picture element part.
Further, in the present invention, it is preferable that a picture element part colored with the aforementioned ink jet system is a picture element part colored with an ink jet system using an UV-curing ink. This is because, after a picture element part is colored with an ink jet system by using an-UV curing ink, UV is irradiated and, thereby, an ink can be rapidly cured, which can be sent to a next step, being preferable in a respect of the efficiency.
A liquid crystal panel having the aforementioned color filter and a substrate opposite thereto and which is obtained by encapsulating a liquid crystal compound between both substrates, has the advantages of the aforementioned color filter, that is, the advantages that color missing and color nonuniformity of a picture element part are not present and it is advantageous in a respect of cost.
In the present invention, in order to attain the aforementioned object, there is provided a process for producing a color filter, which comprises steps: (1) a step of forming a shading part on a transparent substrate, (2) a step of providing a photocatalyst-containing layer in which the wettability of a part irradiated with the energy is changed in a direction of the reduction of the contact angle of a liquid, on a surface of the transparent substrate on which a shading part was formed, (3) a step of forming an exposed part for a picture element part by irradiating with the energy a picture element part forming portion which is a part on this photocatalyst-containing layer on which a picture element part is formed, and (4) a step of coloring this exposed part for a picture element part with an ink jet system, to form a picture element part (which is referred to as the sixth embodiment hereinafter).
In this embodiment, only a part on which a picture element part is formed can be easily made inkphilic by providing a photocatalyst-containing layer on a transparent substrate on which a shading part is pre-formed and pattern-irradiating a picture element part forming portion with the energy on this photocatalyst-containing layer. Therefore, a picture element part with an ink uniformly adhered thereto can be obtained by adhering an ink to an exposed part for a picture element part on which this picture element part is to be formed with an ink jet system and a color filter having neither color nonuniformity nor color missing can be formed.
In the case of the aforementioned sixth embodiment, the embodiment may have a step of forming an exposed part for an ink-repellent convex part by pattern-irradiating a photocatalyst-containing layer on a shading part with the energy and, whereby, an ink-repellent convex part is formed thereon after a step of provision of the photocatalyst-containing layer.
Since an exposed part for an ink-repellent convex part is provided also on a photocatalyst-containing layer on a shading part by the pattern irradiation of the energy, an exposed part for an ink-repellent convex part having the predetermined width can be formed. Therefore, the ink-repellent convex part having the predetermined width can be obtained at a uniform height by applying a coating material for an ink-repellent convex part on this region.
Further, in the sixth embodiment of the present invention, an exposed part for a picture element part may be formed by exposing from the transparent substrate side using the shading part as a mask in a step of forming the aforementioned exposed part for a picture element part. By whole surface-exposing from the transparent substrate side, that is, a side on which a shading part is not formed, only a photocatalyst-containing layer corresponding to a part formed on the upper side of a shading part is not exposed and the other part can be exposed. Therefore, since the energy pattern irradiation can be performed without using a photomask and the like, it is advantageous in a respect of cost.
In addition, the present invention provides a process for production of a color filter, which comprises steps: (1) a step of providing a photocatalyst-containing layer having the wettability of the energy-irradiated part which changes in a direction of reduction of the contact angle with a liquid, on a transparent substrate, (2) a step of forming an exposed part for a shading part on a shading part forming portion on the transparent substrate on which a shading part is to be formed by pattern-irradiating with the energy, (3) a step of providing a shading part on this exposed part for a shading part, (4) a step of forming an exposed part for a picture element part on a transparent substrate on which this shading part is formed by the energy irradiation, and (5) a step of coloring this exposed part for a picture element part with an ink jet system, to form a picture element part (hereinafter referred to as the seventh embodiment).
In a process for producing a color filter in this embodiment, by providing a photocatalyst-containing layer on a transparent substrate and irradiating this photocatalyst-containing layer with the energy, the contact angle with a liquid of an exposed part can be reduced. Therefore, only a region forming a shading part can be first made to be an inkphilic region by simply pattern-irradiating a photocatalyst-containing layer with the energy upon formation of a shading part and, then, a shading part can be formed by applying a coating material for a shading part on this part. Therefore, since a developing step and an etching step after pattern-exposure which have been previously performed upon provision of a shading part need not to be performed. Accordingly, a shading part can be formed effectively. In addition, thereafter, a region forming a picture element part can be easily made to be an inkphilic region, for example, by irradiating the whole surface with the energy. Therefore, when the region is colored with an ink jet system, a picture element part with an ink uniformly adhered thereto can be obtained and a color filter having neither color missing nor color nonuniformity can be formed.
In addition, the present invention provides a process for producing a color filter, which comprises steps: (1) a step of providing a photocatalyst-containing layer having the wettability of the energy-irradiated part which changes in a direction of reduction of the contact angle with a liquid, on a transparent substrate, (2) a step of forming an exposed part for a picture element part on a picture element part forming portion which is a part on the transparent substrate, on which a picture element part is to be formed by pattern-irradiating with the energy, (3) a step of coloring this exposed part for a picture element part with an ink jet system, to form a picture element part, (4) a step of irradiating a photocatalyst-containing layer on at least a border part of the picture element part with the energy, and (5) a step of forming a shading part on the border part of a picture element part irradiated with the energy (hereinafter referred to as the eighth embodiment).
In this case, a photocatalyst-containing layer is formed on a picture element part forming portion which is a part on a transparent substrate on which at least a picture element part is to be formed, and on a shading part forming portion which is a part on which a shading part is to be formed. And a picture element part forming portion of this photocatalyst-containing layer can be first made to be an inkphilic region by pattern-irradiating the picture element part forming portion with the energy. Therefore, by adhering an ink thereto with an ink jet system, an ink is uniformly spread and color nonuniformity and the like do not occur. In addition, a shading part forming portion which is a border part between the picture element parts is not irradiated with the energy and, thus, it remains an ink-repellent region. Therefore, it can be said that it is difficult for an ink adhered to a picture element part forming portion which is an inkphilic region to migrate over a shading part forming portion which is an ink-repellent region. Accordingly, a problem such as the ink mixing does not occur. By irradiating a shading part forming portion between the picture element parts after a picture element part is formed, this part can be made into an inkphilic region. Therefore, by applying this part, for example, with an ink for a shading part, a shading part can be easily formed.
Further, the present invention provides a process for producing color filter, which comprises steps: (1) a step of providing a photocatalyst-containing layer having the wettability of the energy-irradiated part which changes in a direction of reduction of the contact angle with a liquid on a transparent substrate, on a picture element part forming portion on the transparent substrate which is a part on which a picture element part is to be formed, (2) a step of providing a shading part on a border part of the picture element part forming portion on which the photocatalyst-containing layer is provided, (3) a step of forming an exposed part for a picture element part by irradiating the photocatalyst-containing layer with the energy, and (4) a step of coloring this exposed part for a picture element part with an ink jet system to form a picture element part (hereinafter referred to as the ninth embodiment).
In this case, a photocatalyst-containing layer is first formed on a picture element part forming portion which is a part on a transparent substrate on which a picture element part is to be formed. When a material having the higher contact angle with a liquid than the transparent substrate surface in the state before the energy irradiation, is used in this photocatalyst-containing layer, a shading part forming portion on a substrate between the picture element part forming portions becomes an inkphilic region having the smaller contact angle with a liquid rather than a picture element part forming portion on which this photocatalyst-containing layer is formed. For example, by forming a shading part on this inkphilic region with a coating material for a shading part, a shading part can be first formed easily. Then, for example, by irradiating the whole surface on which this shading part is formed with the energy, a picture element part forming portion can be made into an inkphilic region. Therefore, by coloring this region with an ink jet system, a picture element part with an ink uniformly adhered thereto is obtained and a color filter having neither color missing nor color nonuniformity can be formed.
In addition, in the present invention, there is provided a process for producing a color filter, which comprises steps: (1) a step of forming a shading part on a transparent substrate, (2) a step of providing a photocatalyst-containing layer having the wettability of the energy-irradiated part which changes in a direction of reduction of the contact angle with a liquid on this shading part, and (3) a step of coloring with an ink jet system a picture element part forming portion which is a part on a transparent substrate with no photocatalyst-containing layer provided on which a picture element part is to be formed, to form a picture element part (hereinafter referred to as the tenth embodiment).
In this case, a shading part is first formed on a transparent substrate and a photocatalyst-containing layer is formed thereon. When a material having the higher contact angle with a liquid than the transparent substrate surface at the state before the energy irradiation is used in this photocatalyst-containing layer, a picture element part forming portion between photocatalyst-containing layers becomes an inkphilic region having the smaller contact angle with a liquid rather than this photocatalyst-containing layer and a photocatalyst-containing layer which is a border part of a picture element part forming portion is made into an ink-repellent region. Therefore, when an ink is adhered to a picture element part forming portion which is an inkphilic region with an ink jet system, it is difficult for an adhered ink to migrate over a shading part forming portion which is an ink-repellent region. Hence, a problem such as the ink mixing hardly occurs.
Further, in the present invention, there is provided a process for producing a color filter, which comprises steps: (1) a step of providing a photocatalyst-containing layer having the wettability of the energy-irradiated part which changes in a direction of reduction of the contact angle with a liquid on a transparent substrate, on a shading part forming portion which is a part on a transparent substrate on which a shading part is to be formed, (2) a step of coloring with an ink jet system a part on the transparent substrate on which a photocatalyst-containing layer is not formed to form a picture element part, (3) a step of irradiating at least the photocatalyst-containing layer with the energy, and (4) a step of forming a shading part on the photocatalyst-containing layer irradiated with the energy (hereinafter referred to as the eleventh embodiment).
In this case, a photocatalyst-containing layer is provided on a shading part forming portion on a transparent substrate on which a shading part is to be formed. When a material having the higher contact angle with a liquid in the state before the energy irradiation than the transparent substrate surface is used in this photocatalyst-containing layer, a picture element part forming portion between shading part forming portions becomes into an inkphilic region having the smaller contact angle with a liquid rather than a shading part forming portion on which this photocatalyst-containing layer is formed, and a shading part forming portion which is a border part between the picture element part forming portions becomes into an ink-repellent region. Therefore, when an ink is adhered with an ink jet system to a picture element part forming portion which is an inkphilic region, an adhered ink does not migrate over a shading part forming portion which is an ink-repellent region. Hence, a problem such as the ink mixing does not occur. After a picture element part is formed in such as way, by irradiating a photocatalyst-containing layer of a shading part forming portion between picture element parts with the energy, this part can be converted into an inkphilic region. Therefore, for example, by applying this part with an ink for a shading part, a shading part can be formed easily.
Further, in addition, in the aforementioned sixth embodiment and eight embodiment, a step of forming the exposed part for a picture element part and, thereafter, forming a picture element part by coloring the part with an ink jet system may comprise (a) a step of forming an exposed part for the first picture element part by pattern-irradiating a portion of a part on the photocatalyst-containing layer on which a picture element part is to be formed with the energy, (b) a step of coloring the exposed part for the first picture element part with an ink jet system to form the first picture element part, (c) a step of exposing a part forming the remainder picture element part on the photocatalyst-containing layer to form an exposed part for the second picture element part, and (d) a step of coloring this exposed part for the second picture element part with an ink jet system to form the second picture element part.
That is, in any embodiment, a picture element part is formed by forming an exposed part for a picture element part and coloring this part with an ink jet system. And upon formation of the picture element part, picture element parts are divided into the first picture element part and the second picture element part, which are colored with the energy irradiation and an ink jet system, respectively.
When a picture element part is formed by coloring with an ink jet system an exposed part for a picture element part which was converted into an inkphilic region by the energy irradiation, if the distance between the exposed parts for a picture element part is narrow, there may occur a possibility that inks of neighboring picture element parts are mixed over an ink-repellent region between picture element parts upon formation of a picture element part. Therefore, it is desirable that picture element parts are formed in the mutually isolated state upon formation of a picture element part. As described above, when a method of first forming the first picture element part and, thereafter, forming the second picture element part is adopted, for example, the pattern exposure can be performed so that picture element parts are formed alternately upon preparing the first picture element part and the neighboring picture element parts can be in the mutually isolated state upon the first time formation of a picture element part. By forming an exposed part for the first picture element part in the state where a relatively wide ink-repellent region is retained between regions to be colored, which is colored with an ink jet system, a possibility is eliminated that the disadvantages that inks of the neighboring picture element parts are mixed, occur. By irradiating again between the first picture element parts thus provided with the energy to form an exposed part for the second picture element part, which is colored with an ink jet system, a color filter can be formed which has no disadvantages such as the ink mixing and the like.
In addition, in the sixth embodiment and the tenth embodiment of the present invention, it is preferable that the width of the picture element part is formed wider than that of an opening formed by the shading part. This is because, by making the width of a picture element part wider than that of an opening formed by a shading part like this, a possibility that the backlight passes through parts other than picture element parts can be made smaller and color missing and the like can be prevented.
Further, in the ninth embodiment, the tenth embodiment and the eleventh embodiment of the present invention, it is preferable that the wettability on the transparent substrate is less than 10 degrees as a contact angle with a liquid having the surface tension of 40 mN/m. In either embodiment, after a photocatalyst-containing layer having the ink-repellent properties as compared with a transparent substrate is formed, a picture element part or a shading part is provided on a part on which a photocatalyst-containing layer is not formed. And when the wettability of the surface of the transparent substrate is less than 10 degrees as a contact angle with a liquid having the surface tension of 40 mN/m, a liquid is easily spread and, for example, in the case of a picture element part, since an ink for an ink jet is uniformly spread, a picture element part having no color nonuniformity is obtained and, thus, a color filter having the high quality can be obtained.
In the present invention, the energy for exposure by irradiation to a photocatalyst-containing layer is usually the light including the ultraviolet ray. However, when formation of the pattern by light picturing irradiation is performed, an exposed part may be formed using as this energy the photocatalystic reaction initiation energy and the reaction rate increasing energy, and irradiating with the reaction rate increasing energy a part irradiated with the photocatalystic reaction initiation energy.
This is to form the pattern of an exposed part by adding the photocatalystic reaction initiation energy to a photocatalyst-containing layer and adding the reaction rate increasing energy by patterning to a region which received this photocatalystic reaction initiation energy. That is, since the formation of the pattern by light picturing irradiation proposed hitherto by the present inventors used the photocatalystic reaction irradiation energy such as the ultraviolet ray, there was problems that the apparatus is expensive, the handling was difficult, the continuous output was not possible, and the like. However, in this method, since the photocatalystic reaction initiation energy such as the ultraviolet ray is added and the pattern is formed using the reaction rate increasing energy such as the infrared ray relative to a region which received the photocatalystic reaction initiation energy, there is the advantages that the reaction rate increasing energy such as the infrared laser which is relatively low cost and is easily handled can be used upon formation of the pattern.
In the present invention, when two kinds of energies of the photocatalystic reaction initiation energy and the reaction rate increasing energy are used, it is preferable that the photocatalystic reaction initiation energy is the light including the ultraviolet ray and the reaction rate increasing energy is the heat energy. This is because titanium dioxide is suitably used as a photocatalyst in the present invention, therefore the ultraviolet ray is preferable as the photocatalystic reaction initiation energy from the relationship of the band gap of this titanium dioxide. In addition, although it is preferable that the reaction rate increasing energy is the heat, it is preferable that the heat energy is added by the infrared laser. This is because a method of using the infrared laser is relatively low coat and is easily handled.